Thermostatic switch



Oct. 6, 1931. Z|SCIH I 1,826,488

THERMOSTATIC SWITCH Filed April 20, 1928 5 v i INVENTIOR UM/L325.

ATTORNEY Patented Opt. 6, 1931 PATENT. OFFICE GEORGE J. ZISCH, OFNEWARK, NEW JERSEY 'I'HEBMOSTATIC SWITCH Application filed April 20,

v This invention relates to thermostatic control devices in which athermal bar subjected to changes in temperature, is, utilized to openand close an electric circuit, and also for a wide variety of otherpurposes, including :he control of heating and refrigerating sysems.

Various types of similar devices are well known and of commonoccurrence; with few exceptions however they are subject to thedisadvantage of being sluggish in their action, particularly inreversing or changing from one positionto another.

Another objectionable feature resides in [5 the multiplicity ofparts,often uite complicated, and the necessity of ma ing adjustments fromtime to time in such structures.

It is therefore an object of the present invention t provide a form ofthermal change control hat is substantially instantaneous in itsoperation.

A further feature is in the provision of an essentially simple device,composed of a minimum number of parts, which require no adjustment afterinstallation. 7

Another. aim is to produce a thermostatic control switchthat is positiveand dependable in action, capable of changing its position from onecontact to the other in the I shortest posisble time at various degreesof heat, and which is capable of long and continuous service withoutsupervision or attention.

These important results are accomplished by the novel and practicalconstruction and arrangement of parts, as hereinafter described andshown in the accompanying drawings, constituting a material part of thisdisclosure, and in which Figure 1 is a rear plan view of an ment of theinvention. I

Figure 2 is a side elevational view'of the same. 7 x I Figure 3 is atransverse sectional view taken on line 33 of Figure 2.

The device, as shown, consists of a plate base, generally designated bythe numeral 10,

embodiadapted to be disposed in a osition so that 1928. Serial no.271,485.

changes, the other, front side, carrying such electrical attachments asare desire Extending rearwardly from the base 10 is a lug 11 to which isattached one end of a thermostatic bar 12 rigidly held in place, as byrivets 13, the bar being I formed into a curved portion 14 extendinginto a zonesubjected to changes of temperature, and then continuedstraight towards the front, as at 15, passing through an opening 16 inthe base in which the portion 15 of the bar is free to oscillate.

On the front of the base, below the open-' ing 16, is a plate lug 17having set in its center a pivot screw 18, passing through a reentrantlybent spring 19 formed on a fiat metal arm 20 pivotally mounted on thescrew 18 and held by the tension of the spring underadjustablerestraint. I

Carried at the outer end of the arm 20, on its under side, is adielectric channelled block 21 into the recess 22 of which the outer endof the thermostaticbar 15 extends.

Set in the side walls of the recess are screws 2324, the points of thesescrews having silver, platinum or like highly conductive tips 2526arranged to electrically en age similar contacts 27-28, carried near tieend of the bar 15 and with which the tips are in close proximity. 1

As maybe seen in Figure 3, the thermostatic bar 15 is arranged so thatits normal position is such that the contact 28 is in engagement withthe tip 26 and the arm 20 is swung to its ultimate angular position,towards the left, this position being determined by its physical contactwith a stop pin 29 set in the plate lug 17 I I Obviously upon thetransmission of heat to the bar element 14, the member 15 will movetowards the right, breaking the mentioned contact and instantly thecontact 27 will engage the tip 25 and the further accession of heat tothe thermostatic bar will result in turning the arm 20 upon its pivot tothe right, as indicated by the broken lines in Fi re 3.

Clamp nuts 30-31 on the outwar y extending endsof the screws 24-25 serveas binders for conductor clips 32-33 in which are secured cables 34-35so that either may be placed in circuit by action of the bar 15, whichconstitutes a ground connection for the cables.

It will be understood that the effect of heat upon the thermal elementis almost instantaneous, and as the free end of the bar has only to movea fraction of an inch, in practice approximately three-hundredths of aninch, this action is extremely rapid and positive.

It is equally evident that the thermal element upon cooling, even a fewdegrees, will at once move towards its initial position, that is incontact with the tip 26, not being constrained in any way due to thefree movement of the arm 20, the change taking place very rapidly fromone tip to the other, in actual practice ten to fifteen seconds of timebeing consumed.

The application of the switch is of wide scope, its use being indicatedin connection with gas and oil burners and particularly where rapid andpositive control is desirable.

From the foregoing it will be seen that a simple device for this purposehas been disclosed in the preferred form of its embodiment, but it isnot desired to restrict the details to the exact construction shown, itbeing obvious that changes, not involving the exercise of invention, maybe made without conflicting with the scope of the appended claims.

Having thus described the invention, what is claimed as new and desiredto secure by Letters Patent, is

1. I A thermostatic switch comprising a conductive base having anopening, a thermal element anchored to said base, its free portionextending freely through the mentioned opening, an arm pivoted on saidbase to extendin spaced relation parallel to said element, and a pair ofinsulated contacts rigid on the free end of said arm, either of saidcontacts engaging said element upon movement thereof to form electricalengagement whereby said arm may be swung upon its pivot.

2. A thermostatic switch comprising a base, an arm yieldingly mountedthereon, a pair of opposed electric contacts carried in close relationby the free end of said arm and insulated therefrom, a thermal elementanchored on the opposite side of said base and curved to extend throughan opening therein, the free end of said element normally engaging oneof said contacts and being slightly spaced from the other contact tomake electrical engagement therewith when the element is subjected toheat, a stop for said arm when in its initial position, and a frictionalbraking means for said' arm when swun from said stop by said element.

3. Z thermostatic switch comprising a con ductive base having a thermalelement in electric engagementtherewith, a portion of said elementextending into a zone subject to.

changes of temperature and another portion free to move laterally, anarm pivoted to said base to swing in a plane parallel with said element,insulated contacts carried at the free end of said arm engageable withsaid element in accordance with its movement, said arm being turned bysuch contact on its pivot, and electrical connections engaged with saidcontacts.

4. A thermostatic switch comprising a base, a single unitary armyieldingly mounted thereon, a pair of opposed electric contacts carriedin close relation by the free end of said arm and insulated therefrom,and a thermal element anchored on the opposite side of said base andcurved to extend through an opening therein, the free end of saidelement normally engaging one of said contacts and being slightly spacedfrom the other contact to make electric enga ement therewith when theelement is sub ected to heat.

5. A thermostatic switch comprising a base, an arm yieldingly mountedthereon, a pair of opposed electric contacts carried in close relationby the free end of said arm and insulated. therefrom, a thermal elementanchored on the opposite side of said base and curved to extend throughan opening therein, the free end of said element normally engaging oneof said contacts and being slightly spaced from the other contact tomake electric engagement therewith when the element is subjected toheat, and a stop for said arm when in its initial position.

6. A thermostatic switch comprising a conductive base having a thermalelement in electric engagement therewith, a portion of said elementextending into a zone subject to changes of temperature and anotherportion free to move laterally, an arm pivoted to said base to swing ina plane parallel with said element, means associated with said pivot toretain the arm in adjustment, insulated contacts carried at the free endof said arm engageable with said element in accordance with itsmovement, said arm being turned by such contact on its pivot, andelectrical connections engaged with said contacts.

7. A thermostatic switch comprising a base, a thermostatic elementmounted thereon having a portion extending into a zone of heat andanother portion movable through the base, a lug on said base, a unitaryarm pivoted to said lug to oscillate in a plane parallel and contiguousto the movable ortion of said element, opposed contacts rigid with thefree end of said arm, and contacts on the free end of said element toengage said opposed contacts upon movement of said element laterally ineither direction.

8. A thermostatic switch comprising a conductive base having an opening,a thermal element anchored to said base. its free portion extendingfreely through the mentioned opening, a unitary arm pivoted on said baseto extend in spaced relation parallel to said element a pair 0finsulated contacts rigid on the free end 055 said arm, means to adjustsaid contacts relative to said element to en- 5 gage the same uponrelative movement, a

frictional brake on said am and electrical connections for contacts.

In testimony whereof I aflix my si atum.

GEORGE J. ZI CH;

